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Fix Test-Path -IsValid to check for invalid path and filename characters #21358

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Merged
daxian-dbw merged 11 commits into from
Apr 2, 2024
Merged

Fix Test-Path -IsValid to check for invalid path and filename characters #21358

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4bce454
Fix `Test-Path -IsValid` to check for invalid characters
SteveL-MSFT Mar 20, 2024
6ffa7c5
add check of the filename
Mar 20, 2024
ccff28c
limit path check to directory
Mar 20, 2024
5f78260
address Jordan's feedback to check each segment of the path
Mar 25, 2024
1a35cc9
fix case where it's only a filename
SteveL-MSFT Mar 25, 2024
758c7d1
change to use `GetInvalidFilenameChars()` for both path and filename
SteveL-MSFT Mar 25, 2024
9705a60
change test to use variant name so there isn't a null within the output
SteveL-MSFT Mar 25, 2024
9686144
address Ilya's feedback, no need to separate filename and path valida…
SteveL-MSFT Mar 26, 2024
7fe1609
remove path root before checking segments
Apr 1, 2024
12cc221
add comment
Apr 1, 2024
32b9b7c
Avoid calling `Path.GetInvalidFileNameChars` for every segment.
daxian-dbw Apr 1, 2024
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15 changes: 15 additions & 0 deletions src/System.Management.Automation/namespaces/FileSystemProvider.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -1080,6 +1080,21 @@ protected override bool IsValidPath(string path)
}
}

// .NET introduced a change where invalid characters are accepted https://learn.microsoft.com/en-us/dotnet/core/compatibility/2.1#path-apis-dont-throw-an-exception-for-invalid-characters
// We need to check for invalid characters ourselves. `Path.GetInvalidFileNameChars()` is a supserset of `Path.GetInvalidPathChars()`

// Remove drive root first
string pathWithoutDriveRoot = path.Substring(Path.GetPathRoot(path).Length);
char[] invalidFileChars = Path.GetInvalidFileNameChars();

foreach (string segment in pathWithoutDriveRoot.Split(Path.DirectorySeparatorChar))
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@JamesWTruher JamesWTruher Apr 1, 2024

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i suppose it may be a toss up between this and:
pathWithoutDriveRoot.IndexOfAny(Path.GetInvalidFileNameChars().Except(Path.DirectorySeparatorChar)) != 1)

i wondered if it might be faster to not split (but then, of course, there's the linq)

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@SteveL-MSFT SteveL-MSFT Apr 1, 2024 •
edited
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I think in general we want to use less Linq and not more. If there's a perf concern, it might be faster to just replace all the separators with a valid character and analyze the whole string at once, but at the expense of readability and only minor perf improvement I think

{
if (segment.IndexOfAny(invalidFileChars) != -1)
{
return false;
}
}

return true;
}

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42 changes: 42 additions & 0 deletions test/powershell/Modules/Microsoft.PowerShell.Management/Test-Path.Tests.ps1
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Original file line number Diff line number Diff line change
Expand Up @@ -128,6 +128,48 @@ Describe "Test-Path" -Tags "CI" {
Test-Path -Path $badPath -IsValid | Should -BeFalse
}

It 'Windows paths should be valid: <path>' -skip:(!$IsWindows) -TestCases @(
@{ path = "C:\Program Files" }
@{ path = "C:\Program Files (x86)\" }
@{ path = "filesystem::z:\foo" }
@{ path = "filesystem::z:\foo\" }
@{ path = "variable::psversiontable" }
@{ path = "c:\windows\cmd.exe:test" }
) {
param($path)
Test-Path -Path $path -IsValid | Should -BeTrue
}

It 'Windows paths should be inavlid: <variant>' -Skip:(!$IsWindows) -TestCases @(
@{ variant = "wildcard"; path = "C:\Program Files\foo*" }
@{ variant = "pipe symbol"; path = "C:\Program Files|p\foo" }
@{ variant = "null char"; path = "C:\Win`u{0000}dows\System32" }
) {
param($path)
Test-Path -Path $path -IsValid | Should -BeFalse
}

It 'Unix paths should be valid: <path>' -Skip:($IsWindows) -TestCases @(
@{ path = "/usr/bin" }
@{ path = "/usr/bin/" }
@{ path = "filesystem::/usr/bin" }
@{ path = "filesystem::/usr/bin/" }
@{ path = "variable::psversiontable" }
@{ path = "/usr/bi*n/test" }
@{ path = "/usr/bin/tes*t" }
) {
param($path)
Test-Path -Path $path -IsValid | Should -BeTrue
}

It 'Unix paths should be invalid: <variant>' -Skip:($IsWindows) -TestCases @(
@{ variant = "null in path"; path = "/usr/bi`u{0000}n/test" }
@{ variant = "null in filename"; path = "/usr/bin/t`u{0000}est" }
) {
param($path)
Test-Path -Path $path -IsValid | Should -BeFalse
}

It "Should return true on paths containing spaces when the path is surrounded in quotes" {
Test-Path -Path "/totally a valid/path" -IsValid | Should -BeTrue
}
Expand Down